Instead of money or fame — earlier studies have shown that money can only make you happy up to about $75,000 a year — it's empathy that boosts our spirits, a connection that comes from the famous "love hormone": oxytocin.

To show how easy it is to boost oxytocin levels, Zak tested Soboroff's blood before and after he watched a two-minute video about a man dying of cancer. The oxytocin spike in Soboroff's blood levels indicted how strongly he connected with the story.

Zak's previous research found that 100 per cent of social-media users experienced an oxytocin increase. The brain registers seeing photos of friends, he speculates, as a real-time interaction with them.

At the end of the 8-minute video, Zak and Soboroff conclude that "caring about other people increases happiness" and that even faking a smile and forcing yourself to participate in charity work can help hack your brain and boost personal happiness.

"Oxytocin connects us to other people. Oxytocin makes us feel what other people feel. And it’s easy to cause people’s brains to release oxytocin. Let me show you. Come here. Give me a hug," Zak demonstrated in a 2011 TED Talk.

"[You need] eight hugs a day. You'll be happier and the world will be a better place."

Happiness is a lifestyle choice. And, yes, you can fake it 'til you make it.